Non-toxic coating composition, methods of use thereof and articles protected from attachment of biofouling organisms

ABSTRACT

The present invention relates to coating compositions comprising menthol and/or isopulegol and at least one further active ingredient which provide protection to surfaces coated therewith from attachment of various biofouling organisms. These compositions are advantageously used in paint, varnish and sealant formulations.

CROSS REFERENCE TO RELATED APPLICATION

This application is a national stage of PCT/EP2004/003710 filed Apr. 7,2004 and based upon EP 03008352.1 filed Apr. 10, 2003 under theInternational Convention.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to non-toxic coating compositionscomprising active ingredients which provide protection to surfacescoated therewith from attachment of various biofouling organisms. Thesecompositions are advantageously used in paint, varnish and sealantformulations.

The present invention in particular relates to non-toxic coatingcompositions comprising a mixture of (i) menthol and/or isopulegol and(ii) at least one further active ingredient (as further defined below).

2. Related Art of the Invention

Biocides are commonly used in a variety of coating materials havingdiverse applications. In marine paints, for example, biocides protectunderwater structures against attachment of a wide range of biofoulingorganisms, such as algae, barnacles, ship worms and other aquaticnuisance species. In lakes and rivers, biocides are used to protectunderwater structures from freshwater organisms, such as zebra mussels.It has been found that microorganisms, their viscous, bio-organicproduct and absorbed organic matter constitute a tenacious slime whichforms on the surfaces of submerged structures. The initial organisms inthis fouling sequence are bacteria, followed by a biotic progression ofdiatoms, hydrids, algae, bryozoans, protozoans and finallymacrofoulants. Macrofoulants tend to be rugophilic, i.e., settling onroughened surfaces in preference to smooth surfaces.

The fouling of ship bottoms is a longstanding problem, which contributesto speed reduction and increased fuel consumption. The problem offouling is not limited to ships, however, but extends to otherunderwater structures, as well. Buoys can shift due to the excessiveweight of fouling organisms. Wood pilings in berthing facilities undergostructural weakening and ultimate destruction due to ship worm andfungal attack. The fouling of intake screens of municipal water supplysystems can lead to reduced flow rates and accelerated corrosion.Concrete or ferro-cement structures, e.g., dams, are also adverselyaffected by biofouling organisms.

It is understood by those of skill in the art that a marine coating mustbe water resistant in order to provide practical and effectiveprotection. The expression “water resistant,” as used in describing thecomposition of the invention, refers to its ability to provide adurable, protective barrier that can effectively withstand hydrolyticattack and is essentially impermeable to water. Water resistance isintrinsically important to marine coatings because, for example, it isprohibitively expensive to re-coat most items in marine service, as theymust be put into dry-dock or otherwise removed from the water in orderto be re-coated. It is also desirable, for example, to minimize the timeand expense of cleaning fouling organisms from the coated surface. Theprotection provided by a marine coating, therefore, whether it beagainst corrosion, fouling, abrasion, etc., should be effective over aperiod of at least months, and, ideally, over at least several years. Acoating composition that is not water resistant would be short lived inthe water rather than meeting the performance criteria of a marinecoating.

The majority of commercial anti-fouling coatings include organometalliccompounds which are potent biocides that leach over time from thecoating material. Tributyltin (TBT), for example, is known to be highlytoxic to shellfish. Anderson and Dally, Oceans '86, IEEE Publication #86CH2363-0 (1986). Acute toxicity in invertebrates and vertebrates occursat concentrations as low as 1 μg (micrograms) per liter. Laughlin etal., Mar. Ecol. Prog. Ser., 48: 29-36 (1988). Cuprous oxide and zincoxide, which are other commercially used antifoulants, also function byreleasing heavy metals, i.e., copper and zinc, into the marineenvironment.

In latex architectural paints and wood stains, biocides provide in-canprotection against microbiological contamination that can cause odor andchanges in viscosity and color, and protect the dried film andunderlying substrate from damaging microorganisms. Such coatingmaterials must likewise be water resistant in order to provide effectiveprotection to coated surfaces.

Biocides are also conventionally utilized in elastomeric coatings,adhesives, caulks, glazing compounds, joint cements and the like, whichare also water resistant.

Because certain biocides currently used in the above-mentioned productshave been shown to be ecologically harmful, a number of internationalagencies, whose missions include monitoring environmental quality, areurging the curtailment and eventual termination of their manufacture anduse. A proposal has been made by the International Maritime Organization(IMO), for example, that all antifoulant coatings that contain TBT, aswell as other organotin compounds which have a toxic effect on a widerange of marine organisms, would be banned worldwide by the year 2003.Consequently, manufacturers of such products are faced with the prospectof changing existing formulations to include alternative agents thatare, at once, effective in preventing attachment and growth ofbiofouling organisms and environmentally benign. Other criteria thatmust be taken into account in developing acceptable substitutes forecologically harmful biocides include chemical compatibility with othercomponents in the coating composition, physical compatibility with thedried film and substrate to which the coating is applied, the safety ofthose handling or using the substitute agents themselves or coatingmaterials containing them and the cost of their production.

WO 01/95718 relates to non-toxic coating compositions which provideprotection to surfaces coated therewith from attachment of variousbiofouling organisms using mainly terpenes and terpene derivatives, inparticular (−)-menthol, (−)-trans-p-menthan-3,8-diol, (−)-menthylchloride, 3-[[5-methyl-2-(1-methylethyl)cyclohexyl]oxy]-1,2-propanediol,(−)-isopulegol and (−)-menthone. A mixture consisting of equal parts of(−)-menthol and (−)-trans-p-menthan-3,8-diol is described in Example 7(page 15 and 16), which resulted in a lower percentage of settlement ofbarnacles.

It is therefore one object of the present invention to provide paints orcoating compositions with comparable or better antifouling activity,preferably over a prolonged period of time, especially 3-5 years.

SUMMARY OF THE INVENTION

In accordance with a first aspect, the present invention provides a(preferably non-toxic) paint or coating composition comprising

(i) menthol and/or isopulegol and

(ii) a compound selected from the group consisting of

a) menthyl esters of a (preferably natural occurring) hydroxycarboxylicacid having 2 to 6 carbon atoms, which are in turn optionally esterifiedby C₁-C₄ carboxylic acids on the hydroxy group;

b) compounds of formula (I):

wherein

-   -   R¹ represents a C₂-C₆-alkylene radical having at least 1, but        not more than 3, hydroxy group(s) and    -   either R² and R³ independently of one another represent        C_(l)-C₁₀-alkyl which is optionally substituted by 1 to 3        radicals from the group comprising hydroxy, amino and halogen,        or C₅-C₇-cycloalkyl, or C₆-C₁₂-aryl, with the proviso that the        total amount of the carbon atoms of R² and R³ is not less than        3, or    -   R² and R³ together represent an alkylene radical which, together        with the carbon atom which carries the radicals R² and R³, forms        a 5-7-membered ring, it being possible for this alkylene        radical, for its part, to be substituted by C₁-C₆-alkyl groups;

c) compounds of formula (II):

wherein

-   -   R^(a) denotes C₄-C₂₀-alkyl, C₅-C₂₀-cycloalkyl or        -heterocycloalkyl or C₅-C₂₀-alkoxy, C₆-C₁₂-aryl,        C₅-C₁₀o-heteroaryl or C₇-C₁₁-aralkyl,    -   R^(b) denotes an m+w·n-valent aliphatic C₁-C₈ radical, a        cycloaliphatic or heterocycloaliphatic C₃-C₁₅ radical, an        araliphatic C₇-C₂₀ radical, an alkoxy- or acyloxy-containing        aliphatic C₃-C₁₅ radical,    -   A and B independently of one another denote —O—, —S— or —NH—,    -   Y denotes hydroxy, C₁-C₁₀-alkoxy, C₂-C₆-acyloxy, amino, mercapto        or —O-Z-O—    -   Z denotes C₁-C₆-alkylene,    -   w denotes the valency of the radical Y and    -   m and n independently of one another denote integers from 1 to        8, with the proviso that the sum of m +n is not more than 12        (note: these compounds of group c) are particularly        preferred) d) compounds of formula (III):        wherein    -   R═H and k is an integer from 1 to 4, or R═CH₃ and k is an        integer from 0 to 4;

e) compounds of formula (IV):

wherein

-   -   R′ is H or an alkyl, cycloalkyl, alkenyl, cycloalkenyl,        hydroxyalkyl, alkynyl, acyloxyalkyl, alkoxyalkyl, aminoalkyl,        acylaminoalkyl, carboxyalkyl radical or an alkylcarboxyalkyl        radical of the formula —C_(p)H_(2p)COOR′″, wherein —C_(p)H_(2p)        is a straight or branched chain alkylene group in which p is an        integer from 1 to 6 and R′″ is C₁-C₈-alkyl, each of said        radicals containing up to 25 carbon atoms, and    -   R′″ is hydroxy or an alkyl, cycloalkyl, alkenyl, cycloalkenyl,        hydroxyalkyl, alkynyl, acyloxyalkyl, alkoxyalkyl, aminoalkyl,        acylaminoalkyl, carboxyalkyl radical or an alkylcarboxyalkyl        radical of the formula —C_(p)H_(2p)COOR′″, wherein —C_(p)H_(2p)        is a straight or branched chain alkylene group in which p is an        integer from 1 to 6 and R′″ is C₁-C₈-alkyl, each of said        radicals containing up to 25 carbon atoms; with the proviso that        when R′ is hydrogen R″ may also be an aryl radical of up to 10        carbon atoms selected from benzyl and substituted phenyl wherein        the substituents are selected from C₁-C₄ alkyl, hydroxy and        C₁-C₄-alkoxy, nitro and halogen;

f) compounds of formula (V):

wherein

-   -   R^(#) is C₁-C₅-alkyl, C₁-C₈-hydroxyalkyl or alkylcarboxyalkyl        with up to 6 carbon atoms,    -   R^(X) is hydrogen or C₁-C₅-alkyl; and    -   R^(Y) and R^(Z) independently are C₁-C₅-alkyl, with the provisos        that    -   R^(X), R^(Y) and R^(Z) together provide a total of at least 5        carbon atoms, preferably 5-10 carbon atoms, and    -   when R^(X) is hydrogen, R^(Y) is C₂-C₅-alkyl and R^(Z) is        C₃-C₅-alkyl and at least one of R^(Y) and R^(Z) is branched,        preferably in alpha or beta position relative to the carbon atom        marked (*) in the formula (V); and        (iii) a film forming agent.

Herein, the use of the compounds of formula (II) is particularlypreferred. The corresponding aspect(s) of the invention are particularlyvaluable. Correspondingly, any reference to “compounds listed under ii)a) to f)” is also to be understood as a reference to the compounds ofgroup ii) c) alone.

Examples of alkyl groups include methyl, ethyl, n-propyl, isopropyl,n-butyl, sec.-butyl, isobutyl and tert.-butyl. Examples of alkenylgroups include ethenyl, propenyl, 2-methyl propenyl, n-butenyl. Examplesof alkoxy groups include methoxy, ethoxy, n-propoxy, isopropoxy,n-butoxy, isobutoxy, sec.-butoxy, tert.-butoxy.

All of the isomeric forms of menthol and/or isopulegol and the compoundslisted under ii) a) to f), above, may be used in practicing thisinvention, including structural isomers and stereoisomers.

The mixture of menthol and/or isopulegol and the compounds listed underii) a) to f), above, is present in the coating composition in an amounteffective to inhibit the attachment of biofouling organisms on a surfaceto which the composition is applied as a coating.

Preferably, the compounds listed under ii) a) to f) above are present inan amount of from 0.01 to about 50 percent by weight of the composition.

Also in accordance with this invention, there is provided a paintcomprising the above-described paint or coating composition, preferablya marine paint.

There are also provided in accordance with this invention certainmethods of use of coating materials including menthol and/or isopulegoland the compounds listed under ii) a) to f) above, in particular thecompounds of formula II as listed under ii) c) above. One such methodinvolves protecting a surface exposed to an aqueous environment fromfouling organisms present in the aqueous environment by applying (e.g.,by brushing, spraying or dipping) to such surface a coating includingmenthol and/or isopulegol and at least one, i.e. one or more of thecompounds listed under ii) a) to f). Another method entails protecting acoated surface from attachment and growth of undesired fungal organisms,such as molds, mildew and the like by including in the coatingformulation applied to such surface at least one of the above-describedcompounds.

As another aspect of this invention, articles are provided which have acoating of the composition described herein on at least a portion of thesurface thereof, which provides protection against exposure to thedeleterious effects of biofouling organisms.

The coating composition described above satisfies all of the above-notedcriteria for an environmentally acceptable coating product, in that itprovides effective protection against attachment and growth ofbiofouling organisms, while producing no known ecologically harmfuleffect. Moreover, menthol, isopulegol and the compounds listed under ii)a) to f), in particular those of group ii) c), above have been shown tobe compatible, both chemically and physically, with conventional marineand other paint formulations, are safe to handle and can be obtained ata relatively low cost.

DETAILED DESCRIPTION OF THE INVENTION

It has been discovered in accordance with the present invention, thatthe compounds listed under ii) a) to f), above, and particularly thoseof group ii) c) are useful for inhibiting the attachment of biofoulingorganisms on surfaces, particularly those of underwater structures, towhich a coating composition comprising one or more such compounds isapplied, in particular when they are combined with menthol and/orisopulegol. Such a mixture or combination shows a synergisticallyenhanced activity in comparison with menthol and/or isopulegol.

As used herein, the term “biofouling organisms” refers to any and allorganisms that participate in the fouling sequence in both saltwater andfreshwater environments, including, without limitation, bacteria,diatoms, hydrids, algae, bryozoans, protozoans and macro-foulants.

The menthol according to the present invention advantageously is1-menthol or racemic menthol, preferably 1-menthol.

The isopulegol according to the present invention advantageously is(−)-isopulegol or racemic isopulegol, preferably racemic isopulegol.

Advantageous compounds which have been found to be effective antifoulingagents for a prolonged period of time are compounds selected from (ii)a), above, i.e. menthyl esters, in particular esters of 1-menthol, ofbeta-hydroxybutyric acid, alpha-hydroxyisovaleric acid,alpha-hydroxycapronic acid, alpha-hydroxy-alpha-methyl-valeric acid,glycolic acid and lactic acid, preferred is menthyllactate. Thiscompound is commercially available, e.g. as Frescolat ML® (Haarmann &Reimer). Particularly preferred is the ester of 1-menthol and racemiclactic acid (1-menthyllactate).

1-menthyllactate

Menthyl esters according to (ii) a), above, are well known and describedin DE 26 08 226, incorporated herein by reference in its entirety.

Advantageous compounds which have been found to be effective antifoulingagents for a prolonged period of time and are selected from (ii) b),above, are compounds of formula (Ia) to (Id),

wherein R¹ has the meaning described above, preferably R¹ denotes

The preferred compound of (ii) b) is menthone glycerin acetal. Thiscompound is commercially available, e.g. as Frescolat MGA® (Haarmann &Reimer). Depending on the starting material and the preparation methodsused, menthone glycerin acetal can be used as mixtures of opticalisomers or in the form of the pure isomers. Particularly preferred is amixture of diastereomers of formula (Iaa).

The compounds according to (ii) b), above, in particular the formulas(Ia) to (Id), above, are well known and described in EP 0 507 190,incorporated herein by reference in its entirety.

Particularly advantageous compounds which have been found to beeffective antifouling agents for a prolonged period of time arecompounds selected from (ii) c), above. Compounds of formulas (IIa) to(IIj) are particularly preferred.

Particularly preferred are menthol glycol carbonate (IIa), mentholpropyleneglycol carbonate (IIb) and menthol glycerin carbonate (IIc).Depending on the starting material and the preparation methods used, thecarbonates (IIa), (IIb) and (IIc) can be used as mixtures of opticalisomers or in the form of the pure isomers. Preferred are the compounds(IIa), (IIb) and (IIc) as derived from 1-menthol. The compoundsaccording to (ii) c), above, in particular the compounds of formulas(IIa) to (IIj), above, are well known and described in EP 0 583 651,incorporated herein by reference in its entirety.

Advantageous compounds which have been found to be effective antifoulingagents for a prolonged period of time are compounds and are selectedfrom (ii) d), above, are menthyl methoxyacetate and menthyl3,6-dioxaheptanoate, particularly preferred are the menthyl esters of1-menthol. The compounds according to (ii) d), above, are well known anddescribed in DE 191 547 and EP 1 034 161, incorporated herein byreference in their entirety.

A preferred compound which has been found to be an effective antifoulingagent for a prolonged period of time and is selected from (ii) e),above, is N-ethyl-p-menthane-3-carboxamide of formula (IVa) (also knownas WS-3, commercially available) which can be used as a mixture ofoptical isomers or in the form of the pure isomers, advantageous is theisomer of formula (IVb).

The compounds according to (ii) e), above, are well known and describedin U.S. Pat. No. 4,136,163, incorporated herein by reference in itsentirety.

A preferred compound which has been found to be an effective antifoulingagent for a prolonged period of time and is selected from (ii) f),above, is 2-isopropyl-N-2,3-trimethylbutanamide of formula (Va) (alsoknown as WS-23, commercially available).

The compounds according to (ii) f), above, are well known and describedin U.S. Pat. No. 4,230,688, incorporated herein by reference in itsentirety.

The ratio by weight of menthol and/or isopulegol to the total ofcompounds listed under ii) a) to f), above, is typically between 20:1and 1:5, preferably between 10:1 and 1:2. When menthol and isopulegolare used together in the composition, the ratio of menthol:isopulegoltypically lies in the range of 1:10 and 10:1, preferably between 1:5 and5:1.

In a preferred embodimement a combination of menthol, isopulegol andmenthol propyleneglycol carbonate, is used; the ratio ofisopulegol:menthol being 3:1 to 1:2, the ratio of mentholpropyleneglycol carbonate:isopulegol being 2:1-1:5. In a particularpreferred embodiment the ratio menthol propyleneglycolcarbonate:isopulegol:menthol is about 1:2:1.

The compounds used in the present invention may be synthesized fromreadily available starting materials using known synthetic routes or arecommercially available.

Optionally, the compositions according to the invention may comprisecyclic alpha-keto enamines, as described in J. Agric. Food Chem. 49,5383-5390 (2001), preferably5-methyl-4-(1-pyrrolidinyl)-3-[2H]-furanone,4,5-dimethyl-3-(1-pyrrolidinyl)-2[5H]-furanone and4-methyl-3-(1-pyrrolidinyl)-2[5H]-furanone.

Menthol and/or isopulegol and the compounds listed under ii) a) to f),above, may be included in a conventional paint composition as the soleantifouling agent, or added in combination with other antifoulingagents, biocides, antibiotics, and natural products or extracts toproduce an additive or synergistic effect on attachment of biofoulingorganisms. Examples of (non-toxic) antifouling agents includedecalactone, alpha-angelicalactone, alpha-santonin,alpha-methyl-gamma-butyrolactone and alantolactone. Exemplary biocides(fungicides and algaecides) include isothiazolones (such as SeaNine-211), zinc omadine® (2-pyridinethiol-1-oxide, zinc complex),chlorothalonil, and triazine algaecide. A typical example of a suitableantibiotic is tetracycline, which is a registered antifoulant.

Menthol and/or isopulegol and the compounds listed under ii) a) to f),above may also be combined with organometallic antifoulants, such astributyl tin or triphenyl tin, or inorganic antifoulants such as zincoxide or cuprous oxide, to reduce the total amount of (such) toxicantifoulants in a given coating material.

The film-forming component of the composition of the present inventionmay be any component or combination of components that is readilyapplied and adheres to the surface to be protected when the surface issubmerged. The specific film-forming component to be selected for aparticular application will vary depending on the material andconstruction of the article to be protected and the performancerequirements thereof. After a surface is provided with a protectivecoating in accordance with this invention, the active ingredientsmenthol and/or isopulegol and at least one compound listed under ii) a)to f), e.g. a compound of group ii) c), that are present in the coatingcomes in contact with biofouling organisms, thereby preventing theirattachment. A variety of synthetic polymers are useful for this purpose.Examples of suitable polymer resins include unsaturated polymer resins,vinyl ester, vinyl acetate, and vinyl chloride based resins and urethanebased resins. Unsaturated polyester resins are formed from unsaturatedacids and anhydrides, saturated acids and anhydrides, glycols, andglycol monomers. Preferred film-forming components are mixtures ofnatural rosin and vinyl chloride-vinyl acetate co-polymers. A commercialmarine paint vehicle which is suitable for the practice of thisinvention is Amerlock 698, a product of Ameron International, Pasadena,Calif. Comparable marine paint vehicles are also available from Jotan,AS, Sandefjord, Norway.

The coating composition of the invention may include components inaddition to menthol and/or isopulegol and the compounds listed under ii)a) to f), above, and a film-forming component, so as to confer one ormore desirable properties, such as increased or decreased hardness,strength, increased or decreased rigidity, reduced drag, increased ordecreased permeability, or improved water resistance. The selection of aparticular component or group of components to impart such propertiesare within the capabilities of those having ordinary skill in the art.

The coating composition of the present invention may be used in variouspaint formulations, marine paints being preferred.

The percentage of the active agent (be it a single compound or amixture), i.e. one or more of the compounds listed under ii) a) to f),and in particular one or more of the compounds of group ii) c), aboveand, preferably, menthol and/or isopulegol, in the coating compositionrequired for effective protection against biofouling agents may varydepending on the active agent itself, the chemical nature of the filmformer, as well as other additives present in the composition that mayinfluence the effectiveness of the active agent. Generally, the activeagent comprises between about 0.01 and about 50 percent of the coatingcomposition by weight, and preferably between about 0.1 and about 10percent by weight of the composition.

The compounds listed under ii) a) to f), above and, if present, mentholand/or isopulegol may be included in a non-toxic paint, coatingcomposition or paint formulation during the paint/coating manufacturingprocesses or added to the paint/coating base mixture at the time of use.Menthol and/or isopulegol (if present) and the compounds listed underii) a) to f), above, can be simply mixed into the film-formingcomponents. This is known as a “free association” coating, which allowsleaching of the menthol and/or isopulegol and the compounds listed underii) a) to f), above, from the film-forming components. The antifoulingagent may be covalently bound to the resin, known as “ablative orself-polishing coating” and is released only after the bond hydrolyzesin seawater. Controlled hydrolysis permits a slow release rate whilecreating a hydrophilic site on the resin. A new layer of bound mentholand/or isopulegol and compounds listed under ii) a) to f), above, isthen exposed when the hydrolyzed layer is washed away. See also, Tilleret al. in Proc. Natl. Acad. Sci., 2001, 98, 5981-5985, the entirecontents of which are incorporated by reference herein. Furthermore,menthol and/or isopulegol (if present) and the compounds listed underii) a) to f), above, may also be incorporated with slow releasematerials which permit the controlled release of the compounds into thematrix of the coating, thereby prolonging the effectiveness of thecoating and reducing the amount of compounds necessary to produce theantifouling effect. Encapsulation into such slow release materials alsoprotects menthol and/or isopulegol and the compounds listed under ii) a)to f), above, from the harsh chemical milieu of the coating and wouldreduce degradation of the compounds while trapped in the resin, if theywere susceptible to degradation. Examples of these slow releasematerials include: a) microcylinders composed of metallic cylinders ormodified molecules such as1,2-bis-(10,12-tricosadinoyl)-glycer-3-phosphocholine; (b) liposomes;and (c) cyclodextrins.

While not wishing to be bound to a specific theory regarding themechanism of action, it is believed that the active agent of the coatingcomposition of this invention, i.e. menthol and/or isopulegol and atleast one of the compounds listed under ii) a) to f), above, function byproducing an environment at the surface of a coated substrate whichrepels biofouling organisms, thereby preventing their attachment andgrowth on the coated surface. In this connection, it is conjectured thatthe menthol and/or isopulegol and the compounds listed under ii) a) tof), above, act as antifoulants by interacting with the cold receptors ofthe fouling organisms to induce chemotaxis. It is believed that thisinteraction need not be permanent, and accordingly there is no need forthe menthol and/or isopulegol and the compounds listed under ii) a) tof), above, to be irreversibly consumed in order to exhibit antifoulantactivity. It would therefore be desirable to attach the menthol and/orisopulegol and the compounds listed under ii) a) to f), above,covalently to the film-forming agent, thereby obtaining a coating whoseantifoulant ingredient will not be released into the marine environment.The inhibitory effect on the microorganisms may, however, be produced byinhalation, respiration, digestion or imbibition of the active agent bythe microorganisms.

Also within the scope of this invention is any article having a surfacecoated with a coating containing (i) menthol and/or isopulegol, (ii) atleast one compound listed under ii) a) to f), above, and (iii) a filmforming agent. The coated articles of the invention can comprise anymaterial to which biofouling organisms are prone to attach, such asmetal, wood, concrete, plastic, composite and stone. Representativeexamples of articles which may benefit from a coating which inhibitsattachment and growth of such organisms include boats and ships, andparticularly their hulls, fishing nets, berthing facilities, such aspiers and pilings, buoys, offshore rigging equipment, intake screens forwater distribution systems and decorative or functional cement or stoneformations.

Further aspects of the present invention are the following:

The use of a compound selected from the group consisting of any of thecompounds listed under ii) a) to f) above, and mixtures thereof, asantifouling agent.

The use of (a) a compound selected from the group consisting of any ofthe compounds listed under ii) a) to f) above, and mixtures thereof, or(b) a paint or coating composition of the present invention or (c) apaint according to the present invention for protecting a surfaceexposed to an aqueous environment from fouling organisms present in saidaqueous environment.

The use of a compound selected from the group consisting of any of thecompounds listed under ii) a) to f) above, and mixtures thereof, forproducing a marine paint composition for protecting a surface exposed toan aqueous environment from fouling organisms present in said aqueousenvironment.

In the uses stated before the compound is preferably selected from thegroup consisting of menthol glycol carbonate (IIa), mentholpropyleneglycol carbonate (IIb), menthol glycerin carbonate (IIc),1-menthyllactate, menthone glycerin acetal,N-ethyl-p-menthane-3-carboxamide, 2-isopropyl-N-2,3-trimethylbutanamide,menthyl methoxyacetate, menthyl 3,6-dioxaheptanoate, and mixturesthereof.

A marine paint composition comprising

-   -   a) one or more compounds selected from the group consisting of        the compounds listed under ii) a) to f) (in particular compounds        from group ii) c)) above,    -   a film forming agent,    -   optionally, one or more typical additives, and    -   optionally, menthol and/or isopulegol,        wherein the total amount of components a) and, if present, d) is        effective for inhibiting or preventing fouling organisms, when        the marine paint is applied to a substrate and the substrate is        thereafter exposed to sea water.

Further aspects of the invention are stated in the attached claims.

The use of a mixture of (a) one or more compounds selected from thegroup consisting of the compounds listed under ii) a) to f) above and(b) menthol and/or isopulegol is preferred as such mixture shows asynergistically enhanced activity (see Example 2 below).

The following examples are provided to describe the invention in furtherdetail. These examples are intended merely to illustrate specificembodiments of the compositions, methods and coated articles of theinvention, and should in no way be construed as limiting the invention.These examples provide the results of tests conducted to determine theefficacy of certain compounds of the invention in inhibiting settlementof biofouling organisms.

EXAMPLE 1

Antifouling Test Methods

a. Collection and Culture of Barnacles

Adults of the barnacle, Balanus amphitrite Darwin, were collected fromthe Sacred Heart Marine Research Center at St. Mary's College inTuticorin, India. The barnacles were crushed and the nauplius stagelarvae were collected for culture to the cyprid stage following themethod of Rittschof et al., J. Exp. Mar. Biol. Ecol., 82:131-146 (1984).The cyprid is the stage at which the barnacle larva is competent toattach to surfaces. Upon attachment to a surface, the larva thenundergoes metamorphosis into a barnacle.

b. Settlement Assay

Barnacle settlement assays were undertaken using the method describedpreviously by Rittschof et al., J. Chem. Ecol., 11: 551-563 (1985).Briefly, Falcon 50×9 mm plastic petri dishes were filled with 5 ml offiltered seawater at salinity of 33-35 parts per thousand (ppt) and intowhich 3-day old cyprid stage larvae were added. Menthol and/orisopulegol and/or compounds listed under ii) a) to f), above, wereintroduced at various concentrations into the dishes containingseawater. Controls were represented by those dishes in which no testcompound were added. After incubation at 28° C. for 9 hours, the disheswere examined under a dissecting microscope to determine if there wasany mortality. The larvae were then killed with 10% formalin and thenumber of attached and unattached larvae were counted. Settlement datawere expressed as the percentage of the larvae attached to the bottom ofthe dish.

The settlement assay was used to determine the effective concentrationof a number of different compounds listed under ii) a) to f), above. Theeffective concentration (EC₅₀) is that concentration which inhibited thesettlement of fifty percent (50%) of the cyprid stage of the barnaclelarvae present in a test sample. The results are shown in Table II andTable III. The racemic (+) compounds are denoted with the prefix rac-.TABLE I COMPOUND EC₅₀ (mg/ml) 1R, 2S, 5R-(−)-menthol (=l-menthol) 4 *10⁻³ (see WO 01/95718) 1S, 2R, 5S-(+)-menthol 0.1 (see WO 01/95718)rac-menthol 0.1 (see WO 01/95718) (−)-menthone 0.001 (see WO 01/95718)(−)-isopulegol 8.8 * 10⁻⁵ (see WO 01/95718) rac-isopulegol 2.9 * 10⁻⁵menthylmethylether 1.1 * 10⁻⁴ l-menthyl propyleneglycol carbonate 2.2 *10⁻⁶ I-menthyl lactate 2.0 * 10⁻⁶ rac-menthone glycerin acetal 4.9 *10⁻⁵ menthone glycerin acetal 5.2 * 10⁻⁷ d-limonene 2.9 * 10⁻⁵

TABLE II COMPOUNDS ratio by weight EC₅₀ (mg/ml) l-menthol/l-menthone60:40 1.5 * 10⁻⁶ l-menthol/l-menthone/d-isomenthone 60:30:10 2.1 * 10⁻⁷l-menthol/rac-menthone 60:40 3.2 * 10⁻⁷ I-menthol/rac-isopulegol 50:501.8 * 10⁻⁵

EXAMPLE 2

Inhibition of Fouling Organisms Using a Marine Paint CompositionContaining (−)-menthol, rac-isopulegol and 1-menthol propyleneglycolcarbonate Separately and in Combination

A floating platform was constructed using layers of bamboo and styrofoamfloats. The platform was designed with holders to accommodate testpanels measuring 4 inches×12 inches×0.25 inches (1 inch=2.54 cm).

A first experimental paint was prepared, containing a biocidallyeffective amount of cuprous oxide and no other biocide which was used asthe control. This composition consisted of 40 parts by weight of cuprousoxide, 10 parts by weight of iron oxide red, 5 parts by weight ofxylene, 10 parts by weight of butyl alcohol, 5 parts by weight polyamideresin, 6 parts by weight of plasticizer. To this composition was added acombination of 0.5% by weight of rac-isopulegol, 0.25% by weight of(−)-menthol and 0.25% by weight of 1-menthol propyleneglycol carbonate(Composition A). A second paint composition was prepared from the samemarine paint vehicle containing cuprous oxide, to which was added 2% byweight of (−)-menthol (Composition B). A third formulation was made fromthe same cuprous oxide-containing marine paint vehicle, to which wasadded 2% by weight of rac-isopulegol (Composition C). A fourthformulation was made from the same cuprous oxide-containing marine paintvehicle, to which was added 2% by weight of 1-menthol propyleneglycolcarbonate (Composition D).

Solid iron panels having the above-mentioned dimensions were paintedwith the paint formulations thus prepared, placed in the holders in thefloating platform and submerged continuously near the center of BitacCove in San Dionisio Bay (Philippines) for a period of 78 weeks. Thepanels were examined for a few minutes every three months andimmediately resubmerged after photography. After 78 weeks, the panelswere removed and inspected. The numbers of barnacles attached to thepanels were counted. The major fouling organisms included the barnacle,Balanus amphitrite communis, and the rock oyster, Crossostrea cuculata.

The data obtained are set forth in Table III below. These data show thatrac-isopulegol, (−)-menthol and 1-menthol propyleneglycol carbonate eachare effective antifouling agents with settlement rates of 16.1%, 12.2%and 23.4%, respectively. When the three compounds were used incombination at the lower concentrations of 0.5% and 0.25% respectivelythe protective effect was more evident, with a settlement rate of 2.0%.TABLE III Concentration (% by weight) l-menthol % PAINT racemicpropyleneglycol Settle- COMPOSITION isopulegol (−) -menthol carbonatement CONTROL 0   0 0   100 COMPOSITION 0.5 0.25 0.25 2.0 A COMPOSITION —2.0 — 16.1 B COMPOSITION 2.0 — — 12.2 C COMPOSITION — — 2.0  23.4 D

The foregoing example clearly demonstrates that the compositions of thepresent invention containing menthol and/or isopulegol and compoundslisted under ii) a) to f), above, are effective in preventing theattachment of fouling marine algae and planktonic organisms on thesurfaces of underwater structures to which the composition is applied asa coating. These data further show the long lasting activity of thecompositions of the invention and the synergistic effect of thecomponents on each other.

1. A paint or coating composition comprising (i) menthol and/orisopulegol, (ii) a compound of formula (II)

wherein R^(a) denotes C₄-C₂₀-alkyl, C₅-C₂₀-cycloalkyl or-heterocycloalkyl or C₅-C₂₀-alkoxy, C₆-C₁₂-aryl, C₅-C₁o-heteroaryl orC₇-C₁₁-aralkyl; R^(b) denotes an m+w·n-valent aliphatic C₁-C₈ radical, acycloaliphatic or heterocycloaliphatic C₃-C₁₅ radical, an araliphaticC₇-C₂₀ radical, an alkoxy- or acyloxy-containing aliphatic C₃-C₁₅radical; A and B independently of one another denote —O—, —S— or —NH—; Ydenotes hydroxy, C₁-C₁₀-alkoxy, C₂-C₆-acyloxy, amino, mercapto or—O-Z-O—; Z denotes C₁-C₆-alkylene; w denotes the valency of the radicalY and m and n independently of one another denote integers from 1 to 8,with the proviso that the sum of m+n is not more than 12, and (iii) afilm forming agent.
 2. A composition according to claim 1, wherein saidcompound of formula (II) is present in an amount from about 0.01 toabout 50 percent by weight of said composition.
 3. A compositionaccording to claim 1, wherein the compound of formula (II) is selectedfrom menthol glycol carbonate (IIa), menthol propyleneglycol carbonate(IIb) and menthol glycerin carbonate (IIc).
 4. A composition accordingto claim 1, comprising menthol, isopulegol and menthol propyleneglycolcarbonate.
 5. A composition according to claim 1, wherein saidcomposition is a paint.
 6. A paint according to claim 5, which isformulated as a marine paint.
 7. A method for protecting a surfaceexposed to an aqueous environment from fouling organisms present in saidaqueous environment, said method comprising applying to said surface acomposition comprising (i) a compound of formula (II)

wherein R^(a) denotes C₄-C₂₀-alkyl, C₅-C₂₀-cycloalkyl or-heterocycloalkyl or C₅-C₂₀-alkoxy, C₆-C₁₂-aryl, C₅-C₁o-heteroaryl orC₇-C₁₁-aralkyl; R^(b) denotes an m+w·n-valent aliphatic C₁-C₈ radical, acycloaliphatic or heterocycloaliphatic C₃-C₁₅ radical, an araliphaticC₇-C₂₀ radical, an alkoxy- or acyloxy-containing aliphatic C₃-C₁₅radical; A and B independently of one another denote —O—, —S— or —NH—; Ydenotes hydroxy, C₁-C₁₀-alkoxy, C₂-C₆-acyloxy, amino, mercapto or—O-Z-O—; Z denotes C₁-C₆-alkylene; w denotes the valency of the radicalY and m and n independently of one another denote integers from 1 to 8,with the proviso that the sum of m+n is not more than 12, and (ii) afilm forming agent.
 8. A method as in claim 7, wherein said compositionfurther comprises at least one of menthol and isopulegol.
 9. A methodaccording to claim 8, wherein said coating composition is applied tosaid surface by brushing, spraying or dipping.
 10. An article having anunderwater surface, at least a portion of said surface being coated witha composition according to claim
 1. 11. An article according to claim10, wherein said article is a ship hull or fishing net.
 12. (canceled)13. (canceled)
 14. (canceled)
 15. (canceled)
 16. A method as in claim 7,wherein the compound of formula (II) is selected from the groupconsisting of menthol glycol carbonate (IIa), menthol propyleneglycolcarbonate (IIb), menthol glycerin carbonate (IIc), and mixtures thereof.17. A marine paint composition comprising a) one or more compounds offormula (II)

wherein R^(a) denotes C₄-C₂₀-alkyl, C₅-C₂₀-cycloalkyl or-heterocycloalkyl or C₅-C₂₀-alkoxy, C₆-C₁₂-aryl, C₅-C₁₀-heteroaryl orC₇-C₁₁-aralkyl; R^(b) denotes an m+w·n-valent aliphatic C₁-C₈ radical, acycloaliphatic or heterocycloaliphatic C₃-C₁₅ radical, an araliphaticC₇-C₂₀ radical, an alkoxy- or acyloxy-containing aliphatic C₃-C₁₅radical; A and B independently of one another denote —O—, —S— or —NH—; Ydenotes hydroxy, C₁-C₁₀-alkoxy, C₂-C₆-acyloxy, amino, mercapto or—O-Z-O—; Z denotes C₁-C₆-alkylene; w denotes the valency of the radicalY and m and n independently of one another denote integers from 1 to 8,with the proviso that the sum of m +n is not more than 12, and (ii) afilm forming agent b) a film forming agent, c) optionally, one or moretypical additives, and d) optionally, menthol and/or isopulegol, whereinthe total amount of components a) and, if present, d) is effective forinhibiting or preventing fouling organisms, when the marine paint isapplied to a substrate and the substrate is thereafter exposed to seawater.
 18. A paint or coating composition comprising (i) menthol and/orisopulegol and (ii) a compound selected from the group consisting of a)menthyl esters of a natural occuring hydroxycarboxylic acid having 2 to6 carbon atoms, which are in turn optionally esterified by C₁-C₄carboxylic acids on the hydroxy group; b) compounds of formula (I):

wherein R¹ represents a C₂-C₆-alkylene radical having at least 1, butnot more than 3, hydroxy group(s) and either R² and R³ independently ofone another represent C₁-C₁₀-alkyl which is optionally substituted by 1to 3 radicals from the group comprising hydroxy, amino and halogen, orC₅-C₇-cycloalkyl, or C₆-C₁₂-aryl, with the proviso that the total amountof the carbon atoms of R² and R³ is not less than 3, or R² and R³together represent an alkylene radical which, together with the carbonatom which carries the radicals R² and R³, forms a 5-7-membered ring, itbeing possible for this alkylene radical, for its part, to besubstituted by C₁-C₆-alkyl groups; d) compounds of formula (III):

wherein R═H and k is a whole number from 1 to 4, or R═CH₃ and k is awhole number from 0 to 4; e) compounds of formula (IV):

wherein R′ is H or an alkyl, cycloalkyl, alkenyl, cycloalkenyl,hydroxyalkyl, alkynyl, acyloxyalkyl, alkoxyalkyl, aminoalkyl,acylaminoalkyl, carboxyalkyl radical or an alkylcarboxyalkyl radical ofthe formula —C_(p)H_(2p)COOR′″, wherein —C_(p)H_(2p) is a straight orbranched chain alkylene group in which p is an integer from 1 to 6 andR′″ is C₁-C₈-alkyl, each of said radicals containing up to 25 carbonatoms, and R″ is hydroxy or an alkyl, cycloalkyl, alkenyl, cycloalkenyl,hydroxyalkyl, alkynyl, acyloxyalkyl, alkoxyalkyl, aminoalkyl,acylaminoalkyl, carboxyalkyl radical or an alkylcarboxyalkyl radical ofthe formula —C_(p)H_(2p)COOR′″, wherein —C_(p)H_(2p) is a straight orbranched chain alkylene group in which p is an integer from 1 to 6 andR′″ is C₁-C₈-alkyl, each of said radicals containing up to 25 carbonatoms; with the proviso that when R′ is hydrogen R″ may also be an arylradical of up to 10 carbon atoms selected from benzyl and substitutedphenyl wherein the substituents are selected from C₁-C₄ alkyl, hydroxyand C₁-C₄-alkoxy, nitro and halogen; f) compounds of formula (V):

wherein R^(#) is C₁-C₅-alkyl, C₁-C₈-hydroxyalkyl or alkylcarboxyalkylwith up to 6 carbon atoms, R^(X) is hydrogen or C₁-C₅-alkyl; and R^(Y)and R^(Z) independently are C₁-C₅-alkyl, with the provisos that R^(X),R^(Y) and R^(Z) together provide a total of at least 5 carbon atoms,preferably 5-10 carbon atoms, and when R^(X) is hydrogen, R^(Y) isC₂-C₅-alkyl and R^(Z) is C₃-C₅-alkyl and at least one of R^(Y) and R^(Z)is branched, preferably in alpha or beta position relative to the carbonatom marked (*) in the formula (V); and (iii) a film forming agent. 19.A composition according to claim 18, wherein said compounds are presentin an amount from about 0.01 to about 50 percent by weight of saidcomposition.
 20. A composition according to claim 18, wherein thecompound selected from (ii) a), above, is 1-menthyllactate.
 21. Acomposition according to claim 18, wherein the compound selected from(ii) b), above, is menthone glycerin acetal.
 22. A composition accordingto claim 18, wherein the compound selected from (ii) e), above, isN-ethyl-p-menthane-3-carboxamide.
 23. A composition according to claim18, wherein the compound selected from (ii) f), above, is2-isopropyl-N-2,3-trimethylbutanamide.
 24. A composition as in claim 18,wherein said composition is a paint.
 25. A composition according toclaim 24, which is formulated as a marine paint.
 26. (canceled)
 27. Amethod for protecting a surface exposed to an aqueous environment fromfouling organisms present in said aqueous environment, which comprisesapplying to said surface a coating including menthol and/or isopulegoland at least one compound listed under a) to f) a) menthyl esters of anatural occuring hydroxycarboxylic acid having 2 to 6 carbon atoms,which are in turn optionally esterified by C₁-C₄ carboxylic acids on thehydroxy group; b) compounds of formula (I):

wherein R¹ represents a C₂-C₆-alkylene radical having at least 1, butnot more than 3, hydroxy group(s) and either R² and R³ independently ofone another represent C₁-C₁₀-alkyl which is optionally substituted by 1to 3 radicals from the group comprising hydroxy, amino and halogen, orC₅-C₇-cycloalkyl, or C₆-C₁₂-aryl, with the proviso that the total amountof the carbon atoms of R² and R³ is not less than 3, or R² and R³together represent an alkylene radical which, together with the carbonatom which carries the radicals R² and R³, forms a 5-7-membered ring, itbeing possible for this alkylene radical, for its part, to besubstituted by C₁-C₆-alkyl groups; d) compounds of formula (III):

wherein R═H and k is a whole number from 1 to 4, or R═CH₃ and k is awhole number from 0 to 4; e) compounds of formula (IV):

wherein R′ is H or an alkyl, cycloalkyl, alkenyl, cycloalkenyl,hydroxyalkyl, alkynyl, acyloxyalkyl, alkoxyalkyl, aminoalkyl,acylaminoalkyl, carboxyalkyl radical or an alkylcarboxyalkyl radical ofthe formula —C_(p)H_(2p)COOR , wherein —C_(p)H_(2p) is a straight orbranched chain alkylene group in which p is an integer from 1 to 6 andR′″ is C₁-C₈-alkyl, each of said radicals containing up to 25 carbonatoms, and R′″ is hydroxy or an alkyl, cycloalkyl, alkenyl,cycloalkenyl, hydroxyalkyl, alkynyl, acyloxyalkyl, alkoxyalkyl,aminoalkyl, acylaminoalkyl, carboxyalkyl radical or an alkylcarboxyalkylradical of the formula —C_(p)H_(2p)COOR′″, wherein —C_(p)H_(2p) is astraight or branched chain alkylene group in which p is an integer from1 to 6 and R′″ is C₁-C₈-alkyl, each of said radicals containing up to 25carbon atoms; with the proviso that when R′ is hydrogen R″ may also bean aryl radical of up to 10 carbon atoms selected from benzyl andsubstituted phenyl wherein the substituents are selected from C₁-C₄alkyl, hydroxy and C₁-C₄-alkoxy, nitro and halogen; f) compounds offormula (V):

wherein R^(#) is C₁-C₅-alkyl, C₁-C₈-hydroxyalkyl or alkylcarboxyalkylwith up to 6 carbon atoms, R^(X) is hydrogen or C₁-C₅-alkyl; and R^(Y)and R^(Z) independently are C₁-C₅-alkyl, with the provisos that R^(X),R^(Y) and R^(Z) together provide a total of at least 5 carbon atoms,preferably 5-10 carbon atoms, and when R^(X) is hydrogen, R^(Y) isC₂-C₅-alkyl and R^(Z) is C₃-C₅-alkyl and at least one of R^(Y) and R^(Z)is branched, preferably in alpha or beta position relative to the carbonatom marked (*) in the formula (V).
 28. A method according to claim 27,wherein said coating composition is applied to said surface by brushing,spraying or dipping.
 29. (canceled)
 30. (canceled)
 31. (canceled)
 32. Amethod for protecting a surface exposed to an aqueous environment fromfouling organisms present in said aqueous environment, comprisingapplying to said surface a composition comprising: a) menthyl esters ofa natural occuring hydroxycarboxylic acid having 2 to 6 carbon atoms,which are in turn optionally esterified by C₁-C₄ carboxylic acids on thehydroxy group; b) compounds of formula (I):

wherein R¹ represents a C₂-C₆-alkylene radical having at least 1, butnot more than 3, hydroxy group(s) and either R² and R³ independently ofone another represent C₁-C₁₀-alkyl which is optionally substituted by 1to 3 radicals from the group comprising hydroxy, amino and halogen, orC₅-C₇-cycloalkyl, or C₆-C₁₂-aryl, with the proviso that the total amountof the carbon atoms of R² and R³ is not less than 3, or R² and R³together represent an alkylene radical which, together with the carbonatom which carries the radicals R² and R³, forms a 5-7-membered ring, itbeing possible for this alkylene radical, for its part, to besubstituted by C₁-C₆-alkyl groups; d) compounds of formula (III):

wherein R═H and k is a whole number from 1 to 4, or R═CH₃ and k is awhole number from 0 to 4; e) compounds of formula (IV):

wherein R′ is H or an alkyl, cycloalkyl, alkenyl, cycloalkenyl,hydroxyalkyl, alkynyl, acyloxyalkyl, alkoxyalkyl, aminoalkyl,acylaminoalkyl, carboxyalkyl radical or an alkylcarboxyalkyl radical ofthe formula —C_(p)H_(2p)COOR′″, wherein —C_(p)H_(2p), is a straight orbranched chain alkylene group in which p is an integer from 1 to 6 andR′″ is C₁-C₈-alkyl, each of said radicals containing up to 25 carbonatoms, and R″ is hydroxy or an alkyl, cycloalkyl, alkenyl, cycloalkenyl,hydroxyalkyl, alkynyl, acyloxyalkyl, alkoxyalkyl, aminoalkyl,acylaminoalkyl, carboxyalkyl radical or an alkylcarboxyalkyl radical ofthe formula —C_(p)H_(2p)COOR′″, wherein —C_(p)H_(2p) is a straight orbranched chain alkylene group in which p is an integer from 1 to 6 andR′″ is C₁-C₈-alkyl, each of said radicals containing up to 25 carbonatoms; with the proviso that when R′ is hydrogen R″ may also be an arylradical of up to 10 carbon atoms selected from benzyl and substitutedphenyl wherein the substituents are selected from C₁-C₄ alkyl, hydroxyand C₁-C₄-alkoxy, nitro and halogen; f) compounds of formula (V):

wherein R^(#) is C₁-C₅-alkyl, C₁-C₈-hydroxyalkyl or alkylcarboxyalkylwith up to 6 carbon atoms, R^(X) is hydrogen or C₁-C₅-alkyl; and R^(Y)and R^(Z) independently are C₁-C₅-alkyl, with the provisos that R^(X),R^(Y) and R^(Z) together provide a total of at least 5 carbon atoms,preferably 5-10 carbon atoms, and when R^(X) is hydrogen, R^(Y) isC₂-C₅-alkyl and R^(Z) is C₃-C₅-alkyl and at least one of R^(Y) and R^(Z)is branched, preferably in alpha or beta position relative to the carbonatom marked (*) in the formula (V).
 33. A method as in claim 32, whereinsaid composition is a marine paint composition for protecting a surfaceexposed to an aqueous environment from fouling organisms present in saidaqueous environment.
 34. A method as in claim 32, wherein saidcomposition further comprises (a) menthol, (b) isopulegol or (c) amixture of menthol and isopulegol.
 35. A method as in claim 32 whereinthe composition comprises a compound selected from the group consistingof 1-menthyllactate, menthone glycerin acetal,N-ethyl-p-menthane-3-carboxamide, 2-isopropyl-N-2,3-trimethylbutanamide,menthyl methoxyacetate, menthyl 3,6-dioxaheptanoate, and mixturesthereof.
 36. A marine paint composition comprising a. one or morecompounds selected from the group consisting of the compounds listedunder a) to f) a) menthyl esters of a natural occuring hydroxycarboxylicacid having 2 to 6 carbon atoms, which are in turn optionally esterifiedby C₁-C₄ carboxylic acids on the hydroxy group; b) compounds of formula(I):

wherein R¹ represents a C₂-C₆-alkylene radical having at least 1, butnot more than 3, hydroxy group(s) and either R² and R³ independently ofone another represent C₁-C₁₀-alkyl which is optionally substituted by 1to 3 radicals from the group comprising hydroxy, amino and halogen, orC₅-C₇-cycloalkyl, or C₆-C₁₂-aryl, with the proviso that the total amountof the carbon atoms of R² and R³ is not less than 3, or R² and R³together represent an alkylene radical which, together with the carbonatom which carries the radicals R² and R³, forms a 5-7-membered ring, itbeing possible for this alkylene radical, for its part, to besubstituted by C₁-C₆-alkyl groups; d) compounds of formula (III):

wherein R═H and k is a whole number from 1 to 4, or R═CH₃ and k is awhole number from 0 to 4; e) compounds of formula (IV):

wherein R′ is H or an alkyl, cycloalkyl, alkenyl, cycloalkenyl,hydroxyalkyl, alkynyl, acyloxyalkyl, alkoxyalkyl, aminoalkyl,acylaminoalkyl, carboxyalkyl radical or an alkylcarboxyalkyl radical ofthe formula —C_(p)H_(2p)COOR′″, wherein —C_(p)H_(2p) is a straight orbranched chain alkylene group in which p is an integer from 1 to 6 andR′″ is C₁-C₈-alkyl, each of said radicals containing up to 25 carbonatoms, and R″ is hydroxy or an alkyl, cycloalkyl, alkenyl, cycloalkenyl,hydroxyalkyl, alkynyl, acyloxyalkyl, alkoxyalkyl, aminoalkyl,acylaminoalkyl, carboxyalkyl radical or an alkylcarboxyalkyl radical ofthe formula —C_(p)H_(2p)COOR′″, wherein —C_(p)H_(2p) is a straight orbranched chain alkylene group in which p is an integer from 1 to 6 and Ris C₁-C₈-alkyl, each of said radicals containing up to 25 carbon atoms;with the proviso that when R′ is hydrogen R″ may also be an aryl radicalof up to 10 carbon atoms selected from benzyl and substituted phenylwherein the substituents are selected from C₁-C₄ alkyl, hydroxy andC₁-C₄-alkoxy, nitro and halogen; f) compounds of formula (V):

wherein R^(#) is C₁-C₅-alkyl, C₁-C₈-hydroxyalkyl or alkylcarboxyalkylwith up to 6 carbon atoms, R^(X) is hydrogen or C₁-C₅-alkyl; and R^(Y)and R^(Z) independently are C₁-C₅-alkyl, with the provisos that R^(X),R^(Y) and R^(Z) together provide a total of at least 5 carbon atoms,preferably 5-10 carbon atoms, and when R^(X) is hydrogen, R^(Y) isC₂-C₅-alkyl and R^(Z) is C₃-C₅-alkyl and at least one of R^(Y) and R^(Z)is branched, preferably in alpha or beta position relative to the carbonatom marked (*) in the formula (V), b. a film forming agent, c.optionally, one or more typical additives, and d. optionally, mentholand/or isopulegol, wherein the total amount of components a) and, ifpresent, d) is effective for inhibiting or preventing fouling organisms,when the marine paint is applied to a substrate and the substrate isthereafter exposed to sea water.